sponsored by psychohistorian.org
RA: 12h 59m 34.98s
Dec: −70° 52′ 28.6″
Ch: MSA:1012, U2:451, SA:25
Ref: SIMBAD, SEDS
Type: globular cluster
Mag: B=8.72, V=7.79
Select a sketch and click the button to view
Select a photo and click the button to view
This globular was discovered by Lacaille and included in his 1755 catalogue as Class I No. 14, classifying it as a nebula. In his half-an-inch 8x telescope he saw it as "a small faint comet."
James Dunlop observed it from Paramatta, New South Wales, and included it as No. 164 in his catalogue of 1827. Using a 9-inch f/12 telescope, he described it as "a pretty bright round nebula, about 4' diameter, moderately condensed to the centre. This, with the sweeping power, has the appearance of a globe of numerous matter with very small stars in the north following margin. But with a power sufficient to resolve it, the globular appearance vanishes in a very conciderable degree; and the brightest and most condensed part is to the preceding side of the centre, with the stars considerably scattered on the N.f. side. Resolvable into stars of mixt small magnitudes. A small nebula precedes this." He observed the cluster on 5 occasions.
Observed by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "globular, B, L, R, gbM, stars 14th mag, and one 7th mag N.p. the centre; a fine object." On a second occassion he called it "globular, pB, L, p rich, at first gradually, then vspmbM; diameter of the bright part 3', of the loose stars 10'; stars 12..16th mag, and one large one 7th mag, 3' or 4' north of the centre."
RA 12 59 35.0 (2000) Dec -70 52 29 Integrated V magnitude 6.91 Central surface brightness, V magnitudes per square arcsecond 18.45 Integrated spectral type F3 Central concentration, c = log(r_total/r_core); a 'c' denotes a core-collapsed cluster 1.25 Core radius in arcmin 1.00. ["Catalog Of Parameters For Milky Way Globular Clusters", compiled by William E. Harris, McMaster University. (Revised: May 15, 1997; from http://www.physics.mcmaster.ca/Globular.html; Harris, W.E. 1996, AJ, 112, 1487) ]
The RNGC (Sulentic and Tifft 1973) notes that this is a 8.5 mag globular cluster.
"! globular cluster, fiarly condensed"
Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
ASV Journal Vol 24 No 3 June 1971: "easy in 4-inch 64x."
A&ASuppl 13,287; AJ 82,620; MNRAS 156,207
br * = HD112622, V=8.75/0.30. sev br *s in N side with V ~12.5.
15cm - fine mod lg cl w/m8 * due N of center, partially res @ 80x. 195x: 8' diam, core 3' across, br * 2'.5 N of center. wk even concen. sev of brtst *s (m12-12.5) on N border of core. nicely res @ 195x. BS, 24Feb1990, LCO.
This cluster is easy in 11x80 binoculars, lying north and slightly west of the yellowish Delta Muscae. The cluster contrasts well with NGC 4372 some 3 degrees west.
This globular cluster in Musca, viewed with a 15.5-inch telescope, appears very loose and well spread out, star-poor with faint stars resolved at the centre. The bright star shown on the SAO Chart lies to the northwest.
1994-02-23, 00:30, Jonkershoek, 11x80 tripod-mounted, strong moonlight. This cluster and the involved star can be seen easily in strong moonlight.
Location: Campsite (23 16 South 29 26 East)
Sky conditions: 7 magnitude clear.
Instrument: Meade 8" (Super wide angle 18mm eyepiece)
A faint small compact globular cluster gradually brighter to the middle. The one side more gaseous and to the edges some faint outliers. Few pinpoint stars in the field.
8-inch f/10 SCT (EP: 1.25-inch 26mm SP 77x 41' fov; 1.25-inch 18mm SW 111x 36' fov)
A faint small compact globular cluster gradually brightens towards the core. Appears well spread out with faint stars. It is slightly condensed and gaseous in the western part. The rather broad compact core overwhelmed the cluster (111x). Yellow Delta Muscae can be seen 40' arc minutes to the southwest, and an 8.7 magnitude star in the outer fringes to the north inside this cluster. Faint outliers visible with hints of dark lanes more so in the western fringes of the cluster. Discovered by Lacaille and included in his 1755 catalogue.
Date: 2007 03 17, 20:10
Location: Betty's Bay
Instrument: 8-inch Dobsonian, 25mm eyepiece
Sky: clear – bank of cloud to far south.
Notes: Globular cluster. Small fuzzy ball, slightly denser nucleus. Bright star to the east. With higher magnification I could see some graininess but could not resolve any stars in the core.
Sky Conditions:The fainter parts of the Milky Way are barely visible.Haziness only visible on the horizon.Atmosphere stable with little interference.
NGC 4888 has the resemblance of a faint mottled snowball and that the stars in this cluster are partially.The stars in this cluster is relatively condensed and that the nucleus of this globular cluster is slightly compact.This globular cluster measures 9.7'x 7.4.Chart No.248,NSOG Vol.3.
Location:Kambro Padstal, Britstown.
Instrument: 12" Dobsonian Reflector Telescope.
Sky Conditions: Dark moon and stars magnitude and fainter are barely visible with the naked eye.
Transparency of the Sky: The most clear sky possible.
Seeing: Excellent clean sky, limited star flickering and brilliant objects.
Limiting Magnitude: 6.5.
First Impression: Globular Cluster.
Chart Number: No.20(Extract taken out of "Atlas of the Night Sky").
Size:26mm Eyepiece: Field of View: 57/9=6.3'.
20mm Eyepiece: Field of View: 50/8=6.2'.
Size in Arc Minutes:6.2'.
Size of nucleus vs. halo: 9/6.2'=1.4'.
Size of halo: 1.3'.
Globular Cluster is 6.2'*2.0'.
Brightness Profile:Medium Surface Brightness.
Challenge Rating: Easy to observe in a dark sky with a large telescope.
All the individual stars in this globular cluster has a granular appearance where some of the stars is spherically concentrated towards each other. A small clump of stars which is observed as a small chain of stars is resolved. By observing this globular cluster I have found on the central outskirts of this cluster there are some starless patches.
12-inch Dobsonian f5 (EP: 20mm UW, 7mm UW)
Conditions: The fainter parts of the Milky Way are barely visible. Haziness only visible on the horizon. Atmosphere stable with little interference. Limiting Magnitude: 4.9.
NGC 4833 is a very bright globular cluster, oval in shape, and appears as a mottled snowball. It is easy to observe in dark skies and is well resolved into individual stars. The stars are centrally concentrated towards other each other in this cluster. On the outskirts of this cluster bright individual stars are radiating slightly away from each other. Chains of stars are centrally concentrated slightly towards each other, and there are some areas of starless patches. The nucleus measures 15' and the halo measures 8'.
Location:Prince Albert, South Africa
Telescope: Skywatcher 6" Dob
Sky conditions: Seeing: 3/5 , Transparency: Good
Small globular cluster. Easy to find.
At 48x: Slightly brighter core fades gradually to edges. With averted vision some faint stars are barely resolved in the globular cluster itself. 1 bright star to the N and 2 fainter stars to the S.
120x: Stars easier to resolve. Estimate visual size of the core at around 5'. Approximately 40 faint stars resolved and easily counted in globular cluster.
The Messier objects
The Bennett objects
The Caldwell list
DOCdb is still in beta-release.
Known issues, feature requests, and updates on bug fixes, are here:
Found a bug? Have a comment or suggestion to improve DOCdb? Please let us know!
DOCdb is a free online resource that exists to promote deep sky observing.
You could help by sharing your observations, writing an article, digitizing and proof-reading historical material, and more.
Everything on DOCdb.net is © 2004-2010 by Auke Slotegraaf, unless stated otherwise or if you can prove you have divine permission to use it. Before using material published here, please consult the Creative Commons Attribution-Non-Commercial-Share Alike 2.5 License. Some material on DOCdb is copyright the individual authors. If in doubt, don't reproduce. And that goes for having children, too. Please note that the recommended browser for DOCdb is Firefox 3.x. You may also get good results with K-Meleon. Good luck if you're using IE. A successful experience with other browsers, including Opera and Safari, may vary.